Electric heating element



R. G. BRIDGES Nov. 20 1923.

ELECTRIC HEATING ELEMENT Filed March 27.

I L'J F g-Z.

Inventor. & 2

Patented Nov. 20, 1923.

PATENT OFFICE.

RAY GEORGE BRIDGES, OF TORONTO, ONTARIO, CANADA ELECTRIC HEATINGELEMENT.

Application filed March 27, 1922. Serial No. 547,308.

To all whom it may concern:

Be it known that I, RAY GEORGE BRIDGES,

a subject of the King of Great Britain, and

resident of the city of Toronto, county of York, Province of Ontario, inthe Dominion of Canada. have invented certain newand useful Improvementsin an Electric Heating Element, described in the followingspecificat-ion and illustrated in the accompanying drawings, that formpart of the same.

The objects of this invention are, to improve the construction ofelectric heating elements particularly of the flexible kind and todevise a form of element which will be very advantageous in connectionwith the operation of incubators.

The principal features of the invention consist in the arrangement of aflexible resistance wire within a flexible tubular structure ofnon-inflammable electrical insulation, sucg as a tube of fabric wovenfrom asbestos cor a In the drawings, Figure 1-is an underside plan viewof the cover of an incubator show 25 ing one application of myinvention.

Figure 2 is an underside plan view of the cover of an incubator showinga modified arrangement of my invention.

Figure 3 is a sectional View of a portion of an incubator showing thearrangement of the element. f

Figure 4 is an enlarged perspective detail of the form of element shownin Figure 1.

Figure 5 is an enlarged perspective detail of the form of element shownin Figure 2. The particular element of this invention comprises thearrangement of a resistance wire within a. tube of noninflammablemateria'l so constructed as to radiate the heat from the wire element.The form of tube is preferably woven asbestos fabric. This is of such anature that the heat generated by the niohrome wire resistance memberfinds exit between the strands and through the fibresof the fabricitself.

Such an element is of course very flexible and can be utilized for manypurposes such as heating beds. etc.. but it is here shown applied to anincubator for the purpose of distributing the heat in a modified formuniformly over the entire area of the incubator casing.

In the form illustrated in Figures 1 and 4 the woven asbestos tube 1 issufficiently large in diameter to contain a spirally wound heating wire2 but in the form shown in FiguresQ and 5 a straight wire 3 is enclosedin the woven tube.

A heating element thus constructed may be made any desirable length andworked into the structure where the heat is required in a very simpleway without the necessitv of specially formed channels and holders andwithout'danger of short circuiting.

As illustrated in Figures 1 and 2 the tube containing the heating wireis secured to the underside of the cover structure 4 by means of staples5. Small fibre blocks 6 are placed between the legs of the staples andthe element is held thereagainst. These staples may be placed atdesirable distances apart according to the arrangement of the element.The el ement as illustrated in Figures 1 and 2- radiates its heat overthe entire area of the casing to which it is applied. Such constructionis very desirable in incubators so that a uniform temperature will bemaintained over the entire area of the egg tray.

It will be readily understood that a heating element such as describedmay be applied to almost any form of heating appliance where mild heatsare desirable.

What I claim as my invention is A heating element, comprising a tube ofwoven asbestos fibre, and a spirally coiled resistance wire arrangedwithin and enclosed by said tube.

RAY GEORGEJBRIDGES.

